Stroke has been traditionally regarded as a catastrophic event in which maximal damage to brain tissue occurs almost immediately. Recently, clinical and animal research has revealed that the ultimate degree of tissue damage in a stroke is not determined in the first few minutes but instead evolves over a period of hours to days. Amplification of excitotoxic neurotransmitter release, progressive intracellular calcium accumulation, blood-brain barrier compromise, and regional inflammation all may play a role in delayed neuronal death. In conjunction with monitoring physiologic variables, including blood pressure and oxygen saturation, careful observation of clinical neurologic progression may provide an understanding of the "window of opportunity" for acute interventional therapy. The primary objective of this study is to monitor all consecutive stroke patients admitted to the National Naval Medical Center (NNMC) within 24 hr of the onset of cerebral ischemic symptoms and record the progression of clinical deficits over the first 48 hr. A standardized examination (the NIH Stroke Scale) will be performed on admission and again every 8 hr for 48 hr. The patients will be monitored in the neurology ICU and a continuous recording of blood pressure, heart rate, and oxygen saturation will be obtained over this same period. The goal of analysis is to identify the percent of NNMC patients who develop significant progression in the acute post-ischemic period. If substantive progression (30-40%) is found in this population of patients, further investigative and interventional studies are warranted to understand and treat early stroke progression.